In SharePoint 2013, the following applications can be shared across SharePoint 2013 server farms.

"When an authenticated user, whom has never visited a site collection, first visits a site there are a number of tables within the Content database which must be updated". This process might be very expensive and affect the overal performance of the SQL Server for the large farm. It is recommeded to prepopulate the user's table using SPWeb.EnsureUser() API.

SharePoint 2010 enables delivery of hosting environments based on multi-tenancy functionality of SharePoint. However, multi-tenancy has its own limitation and creating multi-tenant farms should be based on the deliberate decision when all pros and cons are carefully evaluated.

SharePoint 2010 provides some support for the Farm Configuration restoration using "Configuration Only" option  http://technet.microsoft.com/en-us/library/ee428326.aspx. However, the limitation of this approach is that not all configuration settings are backed up and can be restored. For example, the following settings cannot be backed up as a part of config-only backup.

Companies with users in local Active Directory environments who is considering using Microsoft Office 365 Beta for enterprises can use "Directory Synchronization Tool" to sync AD users. Using this tool, service administrators can keep Office 365 users, contacts, and groups updated with changes made in the local Active Directory.

Recent release of Exchange Online in Office 365 provides almiost allfunctionality available in Exchange Server 2010, including advanced features, such as voicemail with Unified Messaging. However, there is a small difference in old API that is not supported and some features might work differently in cloud.

By default, the Outlook Web App session time-out is six hours. The session time-out can be customized by using Remote PowerShell (set-OrganizationConfig –ActivityBasedAuthenticationTimeoutInterval).

Using DataSources in PerformancePoint 2010 you have multiple options for the Authentication: Unattended Service Account (does not use  application pool identify) Unattended Service Account and Add Authenticated User Name in Connection String Per-user identity The difference between first two items is quite significant for OLAP data source, regardless these items looks similar. "Unattended Service Account and Add Authenticated User Name in Connecting String setting"  allows to  retrieve the name of the connected user using the CustomData() MDX function. This allows you to do a look up against a value in the cube and dynamically return a cell set. This is often called dynamic OLAP security, which can be useful if it is difficult to align security roles with Active Directory groups. Source

Take into account that SharePoint 2010 PerformacePoint Services should be activated on the Application Server only, not on WFE. Cite from "Microsoft SharePoint 2010 PerformancePoint Services Unleashed" book

Microsoft released SharePoint 2010 Whitepaper where all software bounds and limitations are described

The following table summarize the options of how how you can use Remote BLOB Storage (RBS)  and Microsoft SQL Server 2008 together with  SharePoint  2010

On any server that hosts SQL Server, it is very important that the server achieve the fastest response possible from the I/O subsystem. More and faster disks or arrays provide sufficient I/O operations per second (IOPS) while maintaining low latency and queuing on all disks.

SharePoint 2010 provides the better performance for the List, however some limitations still have place: Maximum number of List Items is 50 million Constrains that block Lists: Max of 8kb of data per list item (not including attachments) Max of six projected fields allowed on joins

Using the Windows Server with the Domain Controller role was always not a good idea, due to the performance issue having the hard drive cache turned off.

Overview
The best way to plan and measure SharePoint performance is by Request Per Second (RPS). The general rule is to plan for 1 RPS (requests per second) per 1000 users, but the number of users, in and of itself, means NOTHING! We can support 100,000 users on a single server farm running on laptop if they each average 1 request every 12 hours, thus producing 100k requests over 12 hours what gives us 2 RPS :)

SharePoint 2010 database model has been changed significantly in the way of distributing data across several databases that makes horizontal distribution of SharePoint 2010 solutions very feasible.

When you start new SharePoint project it's very important to understand the size of a farm you are planning to end up, because it impacts on :

Consider using additional Worker Processes for Application Pool per 600MB of physical memory to add  resilience and enhance performance
In IIS 6.0 and above, an application pool configuration that is supported by multiple worker processes is known as a Web garden. Creating additional worker processes creates additional w3wp.exe processes running in your operating system.
For example, if you have 1.5 GB of free memory at peak use of the server, you could create two additional worker processes on the server.
Details how to configure Web Garden are there. Be aware about some challenges when use Web Gardens
Source

By default, Office SharePoint Server 2007 uses all of the front-end Web servers in the server farm to crawl content in the same server farm. The index server sends requests to each WFE server in the farm. The front-end Web servers get the requested content from the SharePoint sites in the farm and forward that content to the index server for indexing.

When you plan the architecture of you SharePoint farm you should be aware about the following limitations in size of SharePoint objects. Keep your items below those numbers to have adequate performance, otherwise it degrades significantly if you overstep those values

Network response time is one of the important factors that affect SharePoint farm design. Measure the latency between SharePoint servers and users to reorganize servers according the smallest response time. This factor is a key point consideration to determine which of the supported deployment solutions to implement for your Office SharePoint Server deployment. (Latency is the time required for a packet to travel from one point on a network to another).

Be careful when you add users explicitly to SharePoint Groups - it's not recommended approach by several reasons

Virtualized SharePoint solutions became very popular after Microsoft officially announced support of VPC, Hyper-V and 3rd party virtualization for SharePoint farms. So, number of virtualized implementations increased. But, there is one trap, which you need to avoid – is installing SharePoint on virtualized Windows 2008 Server with Domain Controller role.

Activate SharePoint License
Navigate to the Central Administration site and activate SharePoint license – Enterprise or Standard. Different licenses activate different set of OOTB Features for the farm.

 
Plan your farm and network communications before starting actual installation. The first thing to start is designing SharePoint architecture across corporate network. This includes understanding network structure, examining network devices and choosing the right SharePoint topology to fit the existing infrastructure and new requirements.