I have a photo gallery site about famous people and i don't know what meta description i should add on the single-photo pages. By the way, the only thing that changes on the single-photo pages is the image, not surrounding text changes. The problem is that i have over 5000 photos so there is no way i can add manually description on each of them. So i was using the same description for every person's photos e.x (The famous {Person's name}'s photo {photo id}) Of course i was getting multiple duplicate meta description warnings on Google webmaster tools, but i was high on the rankings for my targeted keywords. Then i read an article about duplicate meta tags suggesting that it was better to not have a meta tag at all than having a duplicate. After 2 weeks of the change, my site was almost gone from google, it was appearing on 150 spot or so. So it seemed like the duplicate descriptions weren't doing bad at all. But i would like your opinion and experience. Thanks
meta tags supposedly have little effect anyway. I personally prefer no meta tags over duplicates because to a robot a duplicate meta tag can be an indicator that you may be trying to spam a particular keyword set. I doubt very much this has anything to do with your meta tags, since they have so little effect either way. I would suggest this was more to do with the "news effect".
I prefer to at least use a meta description tag. I think some search engines still use it. It at least helps you get a good description for your site in the search results. That way you don't end up having your site navigation menu or other garbage text as your description. You should try to find some other way to make each meta description more unique. A different id number alone doesn't count as making it unique. Maybe also include the image name, date or whatever else you can dynamically add there. It is true that Google doesn't like duplicate meta tags.
On large sites like this, it is the <title> that you have to worry about. This must be unique. Come up with a scheme like: <title>Name : "The persons name", Where : "The location", PhotoId : "Photo Number" - Myphoto.com<title> Although WMT states these are warning, they are "advise" not "warnings". If you can not make the Description unique, then don't use it at all. And don't use the keyword meta either. But, the SEs must have some text on the page to create the description from. So no text will cause problems
You should add some text to each page. This can be a brief detail about the person and you can use at least one keyword on each page.... I agree with Catanich's approach to make each title tag unique.
I read in many places the google is not using meta tags at all. More than that it penalizes a little bit pages defining meta tags that are not encountered in the content. You can try an experiment, removing at all the meta tags.