If you have a Math-related site, especially one that is non-commercial or mostly non-commercial, and you write me a guest article I'll likely publish it here. If you want to plug a great Math-related cause, write it up and submit it as well. If you have a book (or product) and you send me a copy then I may write a review of it.
You can save yourself time and effort by first sending me a link to your site or telling me briefly about your book and I'll write back telling you if I'll promote it or not.
Occasionally, people write to me asking if I sell ads. I don't. Currently, the only source of revenue for this blog is from Amazon, from books purchased through the widget in the right sidebar or from links to books in articles.
I'm quite busy these days. I write sporadically. But, if you do the work of writing the article then I'll likely publish it the same day or within 24 hours. That's because I like to have content for this blog; I'm just not up to generating lots of it these days.
A couple of examples of guest posts I published are from Alex (Pi Day Challenge) and from Taunia (Rhythm, Rhyme, Results). Neither post was particularly long or elaborate but they both conveyed a message.