Refine blog contribution guidelines (#4533)

Signed-off-by: svrnm <[email protected]>
Co-authored-by: Phillip Carter <[email protected]>

Author: svrnm

content/en/docs/contributing/blog.md

@@ -52,12 +52,14 @@ with the following details:
 - Name of a [SIG](https://github.com/open-telemetry/community/), which is
   related to this blog post
 - Name of a sponsor (maintainer or approver) from this SIG, who will help to
-  review that PR
+  review that PR. That sponsor should ideally be from a different company.
 
 Maintainers of SIG Communication will verify, that your blog post satisfies all
 the requirements for being accepted. If you can not name a SIG/sponsor in your
 initial issue details, they will also point you to an appropriate SIG, you can
-reach out to for sponsorship.
+reach out to for sponsorship. Having a sponsor is optional, but having one
+increases the chance of having your blog post reviewed and approved more
+quickly.
 
 If your issue has everything needed, a maintainer will verify that you can go
 ahead and submit your blog post.