facebook , yahoo groups and twitter ,,, please tell us can we use these all for promotin our sites which contains google adsense ?
If you follow people on Twitter, they generally will follow you back. Other then that you need to simply use the service and people will follow you over time. If you're only sending out your website link every day though, people will stop following you. Provide something of value for them.
There's a number of tools available to help you get more followers - some of them you have to pay for, other can be used for free but usually don't have all the features available in the free version. As soon as you are on to twitter, you'll probably receive heaps of information about all these tools - it usually comes from direct messages as people follow you. Have a look at the differrent tools and see which one fits. If you're still struggling, let me know and I can tell you about some of the tools myself.
Twitter is very good if you use it right, don't just stick to your own agenda give good information which people will find of interest and give them great value, this is very important and you will get plenty of followers and become sucessful at the same time, good luck.