Yes, I mean that the browser allows cookies. I'm limited with what browers I can use at work, so sage doesn't work for me. I'm not stuck with newsgator, but i do want a web-based reader (preferably free). Newsgator allows for me to send a username/password when setting up a restricted RSS feed, but I guess Trumba doesn't support that. Also, I've seen where other web-based readers can read restricted RSS feeds where the username/password is part of the RSS url (http://username:password@www.website.com/feed.rss).
Another thing that you might want to pass by your developer is that several on-line RSS readers have an option for the user to include a username/password when adding feeds, so far I've seen that newsgator and attensa have this feature. I don't know if this is better security/encryption wise that including the username/password in the URL, but it also seems to be something that the RSS feed has to allow.