For optimal benefit – your blog should be on your website, on your domain name – NOT at blogger.com or blogspot.com.
All have blogs – which is smart – but all have their blogs at blogspot.com. Not so smart.
For maximum search engine benefit, your blog posts need to be on your own website, your own domain name. In other words, your blog’s URL should be something like:
(No, linking TO your blog from your main website isn’t the same thing.)
If your blog is well-established and has been around a long time and has some good links to it and has some PageRank (in other words, if Google sees it as a popular/important site) – then it can be valuable, wherever it’s hosted. And having a valuable site link back to your main site is a good thing.
BUT most blogs don’t get that big or that popular – and you lose the search engine benefit of having the blog posts on your own domain name.
You see, when you blog you’re adding keyword-rich content to your site, which the search engines love. And you’re updating your site, showing the search engines that your content is fresh and relevant – which they ALSO love.
You’re most likely to be blogging at an external site if your primary site is built in HTML instead of in WordPress. You have to install WordPress separately, which requires some technical expertise. That’s how my site is set up right now; WordPress is installed in a subfolder of my domain.
However, I’m now converting my site to WordPress for the whole thing – and that’s one reason WordPress is such a popular site-building platform these days. It has that blog functionality is built right in.
Matt Cutts, Google’s spokesperson, recommends installing your blog on your own domain – and that’s good enough for me. If SEO is one of your major reasons for blogging, this is a change you ought to make.