I am trying to create a link between two of my clients websites but they don’t want them to be visible on either website. Is there a way I can do this but still have google recognise it as a link?

Also

When we have videos on our website from say youtube.com, do they count as a link, hence good for SEO purposes?

put image over links
or use font same as background for the links
or use small font

Hidden links are still counted as backlinks as long as it's live but you should also aware that it's not a good practice.

do u know about Link Cloaker ...try it ...i think this helps u a lot ....

If you want to put hidden links on website then use same font color as web page background color, but aware it because it is a black hat techniques according to SEO techniques.

I am trying to create a link between two of my clients websites but they don’t want them to be visible on either website. Is there a way I can do this but still have google recognise it as a link?

Also

When we have videos on our website from say youtube.com, do they count as a link, hence good for SEO purposes?

1. you have many choice to hide your link

A. make the font color same to the background color
B. make the font almost invisible.
3. make one pixel link

2. yes it count as a backlink ..but it will good for seo

because youtube is a very renowned website

Any of the above mentioned link hiding techniques (including the cloaking suggestion) are an easy ticket to having the web pages in question demerited. I'm not saying that the search engines won't find out about it, I'm implying that it is likely that the search engines will most likely determine that your link is being hidden and thus devalue the web pages accordingly.

It is all based on simple logic, if you want to hide something from the Internet visitor but want to make sure the search engine finds it for "SEO" purposes then, the link really isn't of any value. The search engines are pretty swift to recognize this and in most cases will slap your web site promotion efforts with the appropriate penalty.

Ultimately, these "black hat" techniques could lead to a very low PageRank and hurt the client's ranking on SERPs.

Don't try to hide anything.. even the links.......because at some point of time.it will only ruin your rankings and overall position of your website in search engine.

This is unethical tactic of promotion and not recommend from the SEO point of view.

I am trying to create a link between two of my clients websites but they don’t want them to be visible on either website. Is there a way I can do this but still have google recognise it as a link?

Also

When we have videos on our website from say youtube.com, do they count as a link, hence good for SEO purposes?

As everyone has already stated that hiding links is not a good practice, I am curious as to why your two clients want to be linked together without showing it? What are they trying to hide and if they are trying to hide it could it be something that would get them in trouble beyond just penalties by the search engines?

Beyond doing the best work possible for your clients you also have to protect your own reputation and the damage that can be done to your reputation by participating in something that could be perceived or is in fact a bad or illegal business practice could be huge. Be careful.

<a href='thispageatthere.com' style='display:none'>goto thispage</a>

another method

<style type='text/css'>
.hidden { display:none }
</style>
<a class='hidden'>bla,</a>

hidden links make search bots think of Malware
hidden links make users think of malware

If BOTH clients want the link, to the other, put it in in clear visible text,
If the other site is not relevant, put it on a links page
put it on a 'related sites page'
put it on a 'paid referrall page'
recovering from negative searchbot responses- is very much more difficult than getting into google the first time

What CanadaFred said. You shouldn't hide any of your links, just make an image into a link with an appropriate ALT tag-which is good for SEO as well as your users' sanity.

Google is especially too quick to spot any sort of invisible link. By the way, such links may not create magical results anyway, especially when you are talking about one or two.

I have known bloggers who have used such tactics and now they are paying a big price. How? Well, visitors cants find the bloggers' sites on Google search engine result pages. This is truly a high price to pay.

It would seem to me that this type of activitiy is grey hat SEO if not pushing the limits of black hat SEO. Canada Fred, if you are reading this I would like to hear your thoughts on this.

... It would seem to me that this type of activitiy is grey hat SEO if not pushing the limits of black hat SEO.

OK. Hiding links as some form of SEO tactic is a somewhat dark greytone hat SEO technique. Going fishing. See 'ya.