Hi, I'm thinking of starting a company blog. Is it best to have it at www.domain.com/blog or to have a new domain or even blogspot or whatever? company.blogspot.com / www.domainblog.com I guess it's internal links vs external?
Personally I would go with the blog on the same domain. This looks more professional. Hosting your blog on a another domain and filling it with links to your website may trigger some spam filters. Think about how a blog with 90% of its links going to you looks to Google. They still probably wouldn't penalize you right away, but down the road they might.
I had some friends who had a similar debate, although the plan wasn't to host it externally so that they could link back to their own site (and generate backlinks) but to use it as a place to write reviews of 3rd party products and generate linkbait for their main site, so they could place all external links outside of their domain but encourage links back to their main domain. Not sure what your plan is but I'd agree with Vansterdam - it probably looks more professional to put it on your same domain which is what they ended up doing. The potential for using it for SEO purposes is appealing but probably doesn't outweigh the benefits of having it on your own domain.
I would go with the blog on the same domain mainly for the SEO benefit, especially if you are going to be updating it daily or often.
(1) Branding - when people read blog posts, you're branding the main domain name. (2)Frequent updates - google loves frequent, unique updates. Helps the core domain. (3)Backlinks - Backlinks to blog posts help main domain also. (4)New domain - not as good as the existing one, SEO wise. The choice is clear!
I think its better to have same domain itself, because you will also get traffic to your website if the people like your posts in the blog.