I have another query about blog I have told by someone that we should maintain blog on our server and it will be beneficial for our site.
Is it true ? If yes then why?
I asked an SEO expert whether our own website or a popular blogging host would be best for a blog, and he said definitely our own website. I didn't ask why but if it's a blog that interests people it'll act like link-bait, so the links will be coming directly to your site rather than to someone elses. Also, extra pages helps increase your PageRank. I suppose this is more beneficial than having links back to your site from places like Wordpress and Bloglines.
Adding a Blog to a website is a good thing. Google and other Search Engine crawlers will visit your site if there is an update on it. The more you update, the more they visit.
Your friend wanna said that you should add unique posts to your blog and update it regularly.
Yes for backlinks it will help, the only thing is that your server must be on for 24*7.
Well isn't it the idea that all websites be up 24/7?
In any case, a blog adds a lot of "authority" and unqiue content to your domain, from an SEO perspective. It adds overall weight and value to the domain name.
Setting up the blog in a sub-domain on your existing website benefits to your websites search engine ranking. Any new content that is added to your blog will be treated as new content part of your main website.