Q:

Can email signatures in Outlook be hosted externally? 

My company have 10 or so sales reps that all need our email signature that is frequently updated - it contains things like our exhibition dates, any new products logo's we take on etc, so it's a big pain to have to go through the process of explaining how they can update their signatures every time - some even require me to do it on Teamviewer, so it's becoming quite a lengthy process. 
Is it possible to host HTML/plaintext (both, ideally!)  signatures elsewhere to be embedded in Outlook signatures?  I could have sworn I'd seen the feature in Outlook before but can't find it in the latest version. 

A:

As Outlook will allow you to have HTML pages as signatures a simple solution might be to have local pages with an embedded frame (eg below the person's name) which points to an external webpage which you could update with all of the changing information. 

A:

If you're using Exchange 2010, you can set a transport rule to append a signature (that you control centrally), which can use HTML formatting.  Here is an example using this technique that I've been considering. 
It has a few disadvantages, such as not being appended to the latest message, and not being able to add images inline, but you can purchase third party tools to deal with some of these issues.  One such tool that I've found with good reviews (but have not tried) is CodeTwo's Mail Signatures
Alternatively, you can distribute a VB / Powershell script to (assuming you have shared filespace, here) run / schedule, which updates the users signature based on files (even automatically inserting user details from AD).  Here is an example of this approach using Powershell.  This is what my company currently uses (I inherited some VB scripts), though I'm considering transitioning to the first approach as our approach is a little unwieldy.