After TB 6 there are some new updates to use for accessing webmail (hotmail, yahoo, gmail etc).
[Links removed; there is no explanation why they would be needed and they contain executable code which could easily contain malware, and they are not specifically relevant to the portable version - mod Chris]
They dont contain "executable" code. Plus they are relevant to the TB 6 Portable as if someone doesnt update the relevant addon files the existing TB addons wont work to access yahoo, gmail, hotmail, or aol mail.
Just trying to be helpful, but I guess people can google for them if they really want to be bothered.
I think the worry was direct links to an odd Google Docs location instead of the standard link to the WebMail plugin homepage.
Doesn't Thunderbird directly support Gmail, Yahoo and Hotmail now?
Sometimes, the impossible can become possible, if you're awesome!
POP access to Yahoo Mail is currently offered either to paying Yahoo customers, or to specific categories of non-US users. Webmail provides a legal (ToS-abiding) way to use Thunderbird with Yahoo Mail regardless of the category the user belongs to. The same probably applies to Hotmail, though Gmail has no such restrictions. Webmail also helps with restrictive firewalls and some blocked ports.
ArthurL probably linked a development version from Webmail's forums, which are hosted on Google.
My posts are old and likely no longer relevant.