Blogger Guide, Why do I have word verification on my posting form?

Word verification on the posting form is meant to be a spam reduction mechanism for BlogSpot in general. There are two potential causes:

Potential Spam

In this case, word verification is applied to certain potential spam blogs by an automated system. Because this is automated there will necessarily be some false positives, though we're continually working on improving our algorithms to avoid these. If your blog is one of the false positives, we apologize. Having the word verification on your posting form does not prevent you from publishing and does not mean that your blog will be deleted or otherwise punished if it is not actually in violation of our policies.
To avoid further inconveniences when publishing, click the "?" (question mark) icon next to the word verification on your posting form:
That will take you to a page where you can request a review for your blog. We'll have someone look at it, verify that it isn't spam, and then whitelist your blog so it no longer has the word verification requirement.

High Posting Rate

If you make a large number of posts in a single day, you will be required to complete a word verification for each one, independent of whether your blog has been cleared as a potential spam or not. If this happens to you, simply complete the word verification for each post, or wait 24 hours, at which point it will be removed automatically.
This restriction is in place as much to control the load on our servers as to prevent explicit spam. Therefore, there is not a whitelisting review process to exempt individual blogs.
Notes:

• In cases where word verification is required, all posts made via email will be saved as drafts, rather than published.
• This is unrelated to the word verification setting for comments.
• If your word verification is continually reported as incorrect, even though you are entering the correct letters, please try logging out, clearing your browser's cache and Blogger.com cookies, then logging in again to post. Remember to copy and paste your post to a text file first, to keep it safe.