Would I invest in a dot com startup?

Every Joe on the street thinks he can make a quick million or two by starting his own dot com company. Hey Chad Hurley and Steve Chen, founders of YouTube.com did it. Unfortunately there is a saturation of the web sites which promise functionality however they are dependent on your, the user's, data. The first question to ask is why would I want to put my information on a third party web site so that web site founder can make some money. It is the sad truth but most of these companies will not last long. For example let's look at various Social Networks:

• MySpace.com - one of the first site which actually picked up in popularity. Now it is mired in mediocrity and I don't see anything new and exciting happening on the site. Did I mention that they have added Facebook like functionality.
• Facebook.com - I have to say that I was a skeptic when I joined this site however this site offers neat functionality where the user can actually spend time on the site. I am a big fan of Facebook's scrabble application
• High 5 - Started by an east indian and it's being marketed heavily in the east indian community.
• Orkut - I have to say this is probably one of the worst social networks I have come across. It is probably Google's worst purchase.
  
• Kadoo - A new social network site whose UI looks promising however I still don't have an incentive to join this group. I am not into propogating my identity across the internet
• Linkedin.com - I like this website. It's a social network for your professional contacts
• Xing.com - It is a similiar network like Linkedin however this one is popular in Europe
• PageFlakes.com - Someone emailed me asking me to experience this site. Once again I ask the question. Why should I sign up on PageFlakes.com?
• NING.com - This is the UBER social network where anyone can create their own social network. UI is not that great and it is meant as a research application.
  

After I mentioned all of these social networks, how would a investor invest in these kind of businesses? Frankly everyone of these social networks offer similiar if not identical functionaliy. I would probably want to invest in networks which have alot of users and the network has a niche like Linkedin and Xing which only work with professional social networks.

FriendFeed and Kadoo

Today I got my invite to join FriendFeed.com. A personal feed aggregator from various Web 2.0 sites like Blogger, YouTube, LinkedIn, Digg, etc., etc. It also lets you access your friend's personal feed. This way you can get alerts on what your friends up took. I personally don't think it will be popular since users don't want to sign up to multiple Web 2.0 sites. This website is built on top of other websites. I am not too impressed with it. Nevertheless I will use it for awhile since it is still quite new. Good luck to FriendFeed.com site.

BUGS ON FRIENDFEED

• I cannot add multiple blogger sites.
  
• I cannot edit my facebook.com account which is mapped to my FriendFeed account

Things that worry me:
FriendFeed lets you login into your account via your multiple email address (if you register more than one address). This can be a security glitch but the email addresses can also be used by advertisers.

I also came across another web2.0 site called Kadoo.com. They are currently building a Social Information Management System (SIMS). I signed up to be a beta tester on it. SIMS sounds interesting but we have wait and see if it is a cool thing or simply a bust!