So Avus has asked me how you can add a link when you are adding a comment to somebody else's blog. To understand the answer you have to realize that blogspot allows the use of HTML code in your comments (and your blog for that matter, if you switch to html view). So after you realize this, it is just a matter of finding the right code to create what is called a hyperlink.
The code for a link to my site would look like this:
<a href="http://tombocheck.blogspot.com">TOMBO'S BLOG</a>
which creates this:
The <a href= is what tells the computer that you are creating a link.
The "http://tombocheck.blogspot.com" tells the computer where I want my link to GO
The > tells it that I am ready to put in what I want my link to say
The TOMBO'S BLOG is the text that appears on the screen when I am all done
And finally the </a> tells the computer that I am done with my link and want to continue typing normally.
This is what is created when you hit that 'Insert Hyperlink' button in your blogging software, it just happens behind the scenes.
Give it a while, and see how it works for ya!