Currently, certain search engines prefer showing sidebar information instead of content in search results.
Is there a way to hint the search engines which <div> represents content on the webpage, and which <div> represents status data in a sidebar?
You can't control it per sé, but you can hint at it. If you are using HTML5 you can take advantage of the new tags and their semantic meaning. You can use <aside> for the sidebar information and <article> or <main> for the main content. If you are not using HTML5 Google is aware of common semantic use of class names to identify parts of a page. This includes header, footer, content, etc. In fact, it is this list that helped to influence many of the new HTML tag names.
Also consider that there is a check list for how a link is made in the SERPs. Titles if less than about 70chrs will be used to create the link. As well, some criteria is applied to determine the snippet. The description is examined first, then the first H1 header. Next it is the first paragraph that tightly keyword matches the title, description, and H1 tags. If the description is too long or does not keyword match the title tag, then the first H1 is examined and so on. The list of criteria is examined in HTML read order so if your sidebar appears above your content in the raw code, it is up for examination and possible use instead of your actual content.
I have the best results paying close attention to the description meta-tag and H1 tag and making sure each supports the title tag keywords. This is a fragment of the headline read order which I find helpful. When done right, meaning not too long and keyword supportive, the description meta-tag is picked up as the snippet in the SERPs. Otherwise the H1 tag is picked up assuming is passes muster. (and so on...)
I hope this clears things up.
