Microsoft Outlook is an email client and not a host for email. While you may use Outlook as a program to access your email, your email may be hosted by Office365 or another Microsoft email hosting service, on an internal Exchange server, or even with a company such as Google or Yahoo.
Outlook Web Access is different, and can be used to access Office 365 for business and other Microsoft Exchange hosted email. Outlook.com (formerly hotmail.com) is an email service that has email for personal use.
MatchMyEmail is NOT an Outlook plug-in like other products such as Linkpoint 360 and Outlook for Salesforce. MatchMyEmail does not affect Outlook in any way; use Outlook the way you always have and MatchMyEmail will do the hard work of syncing and uploading emails and their attachment to Salesforce.com in background and in the cloud. MatchMyEmail will access the emails that you see in Outlook and that you want to sync with Salesforce.com at the server or network level.