I had a look at Jonas Deibe's blog today (Jonas is the foremost CRM expert at Microsoft Sweden) and found an interesting tip I thought I'd tell you about.
For instance, if you have a sharepoint integration with CRM where there is an IFRAME on the accounts showing the customer site in SharePoint, and the customer site shows the CRM account in an IFRAME also. It might be advisable to not show the IFRAME showing the sharepoint site, if it is shown in Sharepoint (=loop). Then you could use this technique to handle this.
There are certainly a million other uses for this, so enjoy!
CRM and SharePoint Consultant