I'm adding a blog to my web page. It will just be used to discuss things related to my main pages, not the focus of the site. From an SEO point of view will having my blog comments be do-follow be good or bad for me?
If your primary domain that you are installing the blog in a subfolder is highly authoritative, expect to have a higher level of spammers visit your site as a result, looking to get blog comment links (if you 'follow' them). Having 'follow' links can reward good content contribution and conversation. If you are on a platform like Wordpress, you could find a plugin to manually override the 'follow' function of a link on a per post basis, and actually reward those contributors to the site that deserve it, and keep the rest as 'no-follows'. It definitely has the potential to be bad for SEO purposes. If you are seen as a spammy site, you have the potential to be devalued as a result in the SERP.
Keep it do follow for some period so that people come to your blog to comment which helps you to bring in some traffic. no follow straight away may not interest certain bloggers as you are not interested to share link juice with them
Right, keep it dofollow for initial stage of your blog. But you can do one thing to prevent spamming that you can make it like comments get displayed only after approved by you. By doing so, you can know that which comments are spam and which comments are genuine for your blog.
initially do follow, so that your site gets improved ranking then no follow to avoid the spam from bots
Well it's not bad for you after all. You may just receive tons of spam comments if you make the links on your blog a no-follow link.
if your blog is new then i recommend to make your blog do follow...it will bring you initial traffic which will boost your traffic and alexa rank both.
Dofollow blogs helps to increase your blog traffic, so, you can keep it for sometimes but you should use moderation for new comments that helps to spamming.
do-follow is always the way to go, but be prepared to moderate. Akismet is good, but not perfect and will let a lot through and sometimes even block good stuff. I am on the fence as to if it is worth it or not.