Today I found interesting "bounds" limitations of the Project Server 2010, that are platform related.

When you have error in SharePoint 2010 you are provided with Correlation ID that identify that error.

SharePoint 2010 Term Store is able to store the following number of items: 

SharePoint 2010 releases in variety of type, editions and licence versions. There are

SharePoint 2010 ships with 3 new master pages additionally to the default.master page

SharePoint 2007 provides the out-of-the-box (OOTB) approval workflow, but unfortunately this workflow doesn't work with groups.

Unlike crawling SharePoint sites on SharePoint Server 2010 or SharePoint Foundation 2010 the crawler cannot automatically crawl all subsites in a site collection from previous versions of SharePoint Products and Technologies. Therefore, when crawling SharePoint sites from previous versions, you must specify the URL of each top-level site and each subsite that you want to crawl.

SharePoint 2010 provides you rich JavaScript functionality extending the client model. New functionality comes with the SP.js that locates in 14(Hive)\TEMPLATE\LAYOUTS\SP.js

SharePoint 2010 removes Site Directory template, and you can't create it anymore (almost), but for the compatibility reasons the migrated sites will show the Site Directory.

When you try to print the SharePoint 2010 page you will find that site header and navigation is printed with you content. Very often you don't need that service information and would like to see the page content only.  This can be easily done via the custom CSS  that turns off the unnecessary elements from the printing.

Microsoft published Search functionality overview for the SharePoint 2010.  More details there

SharePoint 2007 had limitation of folders support for the KPI Lists. Whenever you tried to set Folder as a source of your KPI, SharePoint gave you an error that folder can't be selected.

SharePoint 2010 monitors changes of themes. So, when a preinstalled theme is modified, a new theme called Custom is created automatically after the theme changes have been applied.

No SSP – the new model of Serviced Applications replace the deprecate SSP in SharePoint 2010. The Service application architecture allows a set of services to be associated with a given Web application and a different set of services to be associated with another Web application (By publishing a service application, it can be shared across server farms) The BCS is actually a platform that provides a SharePoint-based framework for creating Office Business Applications, or OBAs. BDC Entites became “external content type (ECT) “. Business data can be exposed as Office Word document properties and can be inserted into documents. Users can interact with business data using the familiar Outlook interface, and take the data offline using the new SharePoint Workspace Claims based Identity, a system to describe, trust, and act on the identity of users accessing SharePoint. It is a capability that exists in addition to Windows based Authentication (NTLM/Kerberos). SharePoint Server 2010  Technical Preview implementation of Claims based Identity is standards based. Customers deploying SharePoint Server 2010 Technical Preview, can use any protocol or service that implements these standards to provide Identity to SharePoint. In addition, when applications running on SharePoint need to make external Web service calls, SharePoint will issue a SAML token that identifies the user and application pool identity. For more information on Claims based Identity standards, see [WSTrust], [WS-Security], [WSFederation] and [SAMLToken1.1] Сomposition Application that allows to connect to external data using SharePoint Designer 2010 to create an external content type. This external data can now be leveraged within the Office clients such as Word or Excel. Custom task panes in Outlook can use this data from external line-of-business applications to augment a person's contact card when selected such as their company's recent orders, etc. User profile service export data back to Active Directory and Lightweight Directory Access Protocol (LDAP). In Microsoft SharePoint Server 2010, a user profile service administrator can define properties that will be exported back to the Active Directory. A popular scenario for the export functionality is to send a user’s picture back to be stored in Active Directory Visio 2010 supports - you can create workflows in Visio 2010 and export them into SharePoint Designer 2010 to add business logic and additional rules Internal SharePoint Designer 

SharePoint 2007 Web Services model provided limited functionality to manage SharePoint farm over the web model. The reason of this is that SharePoint 2007 was considered as a stand-alone product, without Web 2.0 features and Cloud services.
In nowadays, we are moving to Online services and rich Web Services model is one of the requirements for all products we are using, especially for enterprise wide applications that can be scaled globally.
The release of SharePoint 2010 takes into account Web 2.0 and Cloud trend and exposes all new functionality that is exposed not only via SharePoint API, but via Web Services, WCF model and JSON protocol.
Microsoft direction is to provide you rich web API to expose all stand-alone power of SharePoint over the wire.

SharePoint 2010 Timer Jobs undergo changes are in the management and in configuration.

SharePoint 2010 Site Changes

SharePoint 2007 use the English-US language for the Spell Checker in OOTB MOSS Content Editor, but there is no UI options to change its language to other one.

What’s new in Services
SharePoint 2010 provides the new architectural model of services, deprecating the SSP approach completely. Instead of this SharePoint 2010 provides new approach of the isolated set of services that can be easily shared across web applications and site collections

User Interface Changes
Customers familiar with the previous version of SharePoint will notice some major changes to the user interface in SharePoint 2010.

To open a List in edit mode and add the new Web Parts you usually need a SharePoint Desinger. But there is a trick, how to open a List in Edit Mode and have the “Add Web parts” window is displayed. Everything you need to do is to add  "ToolPaneView=2" parameter to the List URL.

SharePoint content crawling is limited by the number of sources and repositories you are crawling.

When you administrate SharePoint or develop new application one of the most frequently used console command is STSADM. This command provide you specifc access to the SharePoint functionality via commands. STSADM has a huge number of commands, which is hard to find from the results it prints in console.

SharePoint security model is officially called as "Three-tier administrative model". Such model allows to centralize configuration and management tasks, and differentiate administrative roles to be delegated to the appropriate people.

SharePoint provides you several navigation providers to be used for you sites.

SharePoint development relies on “12-hive” folder and each who writes code for SharePoint uses that folder intensively. SharePoint uses that folder to store features, log, content types are other stuff.

There are several ways to build disconnected systems based on SharePoint. But all of them have pros and cons. The following table shows what each of disconnected scenarios supports.