How detrimental is duplicate page content?

[mycity4kids]

We have a local site wherein we have multiple advanced search parameters based on facilities available at a particular place. So for instance, we list a set of fun places to take kids to in a city. We have a page for this. We now have ability to select a list of fun places that have parking facility available or which are "outdoor". Now we use parameters to address these additional search criteria. Would search engines treat them as duplicate pages and in case it would how detrimental would this be?

[TranslateMediaLtd]

Duplicate content is detrimental but the issue is relatively easy to solve. Just ensure you add rel="canonical" tags to the duplicate pages to allow Google to identify and rank the preferred page.

[mycity4kids]

Does rel="canonical" only indicate to Google the preferred page or does it also indicate that the content on the current page is duplicate in nature? Should it be better if we actually remove these pages from the index by providing for a "noindex" on the page?

[TranslateMediaLtd]

I guess it depends how much duplication there is. If the pages contain completely duplicate content with no unique content at all then the best move would be to noindex or nofollow them. Otherwise rel=canonical is probably fine.

[AlanMosley]

If you no-index, any link pointing to that page will waste its link juice.
If you must do that no-index,follow so the link juice  can flow back out.
if your site is mainly duplicates then you have a problem, but if it is just a few pages, don't worry.
google will give credit to one page and will disregard the others.

[gfiorelli1]

As others had answered before, if the pages with parameters are just a consequence of a filter, but don't actually add nothing relevant (aka: substantially duplicated of the not parametered URLs) or nothing all, than the best idea is having those URLs with noindex meta robots.

This will ensure that those pages, if they were crawled, will disappear from the index.

But this is just a general rule, because can exists many variations to that same rule (and we don't know how really has been developed your site).

For instance, if those pages cannot be physically crawl because the filters are behind a Javascript selector (something that can be verified disabling Java in the browser), then you should not suffer issues and, eventually, using the meta robots "noindex" should be just a prevention not really an intervention to something already happened.