1] I've never used Yahoo groups, but I believe its a true Mailing list (Majordomo) and not just web-based. The email notifications are done by all web-based programs as well...but that is not the distinguishing factor. What differentiates true mailing lists is that the users **also** reply from their email clients. Is what you need ?
We use DirectAdmin on our Linux servers and that has Majordomo built in...though I do admit never having used it. So,
Yes we can offer it. If you need it, will make sure it works for you.
Web-based programs are a different breed...they can be in Php or Perl...basically a threaded BulletinBoard. I would presume you have already researched & found the software needed for this.
2] Virus scanning for uploads is going to tricky...because RTL scanning doesn't always kickin for uploads. We have Virus scanning on our Windows server...and it never kicks in for user uploads, but does prevent user from viewing an infected file.
I'm not sure of this part really, because virus scanners behave how they made by the developers.
3] Sure, just get a SSL at rackshack.net for $19.95 and it can be installed free for your site.
4] We do provide reliable and quality services in budget prices, but **true** Phone support is not possible in that price range, because it entails very large overheads. However, Ticket, Email and livechat is available
5] We've been web hosting since 1999. We own the hardware also...colocated in XO.com Fremont, Datacenter. If you need to Colocate your own server, that can be done rather inexpensively as well.
Your diskspace+Bandwidth requirements have not been mentioned but we have a 200 Mb+10 Gb account available for $5/month. You can check full pricing here...
http://www.netspaceinternet.com/mana....html#ultraweb