Every time I get new client, I had to build separate web 2.0 properties (blogs) for individual clients which is very time consuming (it's solely for link building and content marketing purpose). It's also a part of my link building strategy for my clients sites.
To reduce the time consumption, I'm planning to buy few new domains, set up blogs which will cover many different niches like I mentioned above and publish contents on them (of course with appropriate category and tags). I'll also do SEO for these blogs to make them authority sites.
Now my question is, if I invest in such blogs like buying domains and hosting, are the links from these blogs to my clients sites pass any good value?
I'm confused because I'm planning to cover many niches in one blog. Is covering many topics make the blog site as spam site? I also found many blogs over the internet with real high Page Rank but covering many topics too.
Do you guys have any suggestion for me in this regard?
Thanks in advance for your response.