Hi,
I am sure most Web 2.0's will allow you to create blogs/profiles/etc in Spanish. Even if their site (eg. Wordpress) is in English, they do not usually prevent you from writing your articles and other material in your home language.
Google does prefer links that come from material that is relevant to your web site, including the language used. While English links will help you, Spanish-language links and material should be much more helpful.
It is fine to use tools like GSA with Spanish sites.