scrapebox question on blasted sites relevancy

Do the blogs you want to scrapebox blast have to be related to your keyword/site?

For example I hear a lot of people talking about lists they have made and will share or sell to others but obviously these lists have nothing to do with the niche the other guys sites are on.

Any help would be appreciated

Edit: Man I really could have named this thread better...

I think it's a question of what subject/category Google puts you in.

This is what I do:

I use the keyword tool and enter my website for Google to bring back keywords it deems relevant.

I then go from there. Maybe use the Scrapebox keyword scrape tool to bring back more keywords if you're still short.

Then deselect 'use proxies' and select 'Yahoo' - you're now good to go. Remember to put the incompleted keywords back into the harvester and keep going until it's gone through all the keywords.

Then use the blog analyser, if you're going to comment manually, or just do 2-3 test blasts.