Google Friend Connect lets you easily add robust, social features to your website. You can grow your community by making registration simple, so more users join and explore your site. You can also encourage activities to get users commenting, rating, sharing, etc. Besides that, it is simple setup. What you need to do is just copy and paste snippets of code to get started.
There are too many advantage to use Google Friend Connect such as simple setup, Copy and paste, Grow your community, Social gadgets, Get to know users, Send newsletters, More relevant ads, etc. You can find more at Google Friend Connect website. Without wasting time, let me introduce some interesting feature which may benefit your website immediately.
1. Recent Visitors - This gadget will list the recent Visitors to your site to let you track your visitors immediately.
2. Featured content - This gadget will display content from your site based on the interests of your site's visitors. Besides that, this gadget will automatically display content that matches the interests expressed by your site's visitors by using Google site search. It is good for you to better understand your visitor from Google site search.
3. Interests poll. You can use this gadget to ask your visitors questions relevant to your site via a poll that adds to their profile. Those answers can enhance AdSense and the featured content gadget. This gadget works in concert with the Interests feature.
4. Members Links - Members Gadget linking directly to member sites
5. Top 10 Members - Lists top 10 members of your site, accoring to the number of times a member visits your site.
6. Brain Fire - Stimulate your brain. See how fast you are with numbers. If the normal level is easy, try the hard one. Use this gadget to do a regular mental exercise. Try it now and show off your best time.
7. Comments Box - Last but not least, you can just Google Comments box to let users post comments and video links. Posts can apply to a specific page or an entire website. Moreover, you are no longer need to use other third party comment box.
What you need to do is signup an account at Google Friend Connect. Then add your site before get your desired gadget. To conclude, I prefer to use Google Gadget to avoid any unnecessary advertisement in my site.
Source: http://www.google.com/friendconnect/