I'm going to guess you already know what a blog is. "Dofollow" means that links from that blog are set to be "followed" by search engine robots.
Dofollow means you can gain "link juice" from having your site links on the blog which will increase your pagerank. Nofollow is the opposite but it still helps you improve your search engine rankings because each link you have on another site will be counted as a backlink. Just no affect on pagerank.
Dofollow blogs can be tough to find without the help of software. (Scrapebox, for example.) So if you're on the hunt for DF blogs specifically you'll probably need to purchase it. But don't ignore nofollow entirely. Having nothing but dofollow links can raise red flags with Google.
I think you are asking about links in blog comments. You can check the source code of the page. If you see rel=nofollow in the hyperlink, link is no-follow. If not it is do-follow. You don’t need to do this manually. You can download a no-dofollow plug. The plugin will highlight no-follow links in red color.
Install NoDoFollow Add-on in your Mozilla Firefox browser and active that add-on. You will see links in two colour. Among them the red links are NoFollow and blue links are DoFollow.
You can google to search a related blog on any niche. The exact query and related google querues are on my blog so i can not post the link of my site here. You can check it from my signature.
Dofollow is the html code which make your link which you place on your website dollow. Which means your link is crawlable for google and other search engine. if the link in nofollow then the search engine never crawl such type of link.
Or check it manually: 1. <a></a> tag: if rel="nofollow" attribute then link is nofollow 2. robots.txt: if you see "Disallowed" for some pages - then those pages are no follow 3. check meta "robots" tag: if "nofollow, noindex" then this page is nofollow
or you can highlight a link, right click and click view selection source. The a href tag should not have no follow in it, then you know for a fact its do follow.
Dofollow Blogs are those whose links Google follow and nofollow Blogs whose links Google does not follow. By viewing the source page you can find which blog is dofollow.
Do Follow blogs are blogs which turning the No-Follow tag off, enabling do-follow of out going comment links.