A trackback is sort of like a blog conversation. When you write a new article to your blog and it links or references another blogger’s article you can do a trackback to their entry. What this does is leave a truncated summary of your blog post on their blog entry – it’s sort of like your blog telling someone else’s blog that you wrote an article mentioning them. Trackbacks often appear like comments.
This is a good technique because like leaving comments a trackback leaves a link from another blog back to yours for readers to follow, but it also does something very important – it gets the attention of another blogger. The other blogger will likely come and read your post eager to see what you wrote about them. They may then become a loyal reader of yours or at least monitor you and if you are lucky some time down the road they may do a post linking to your blog bringing in more new readers.