A Competitor Links to Me... With a Hidden Link

In the home page there is an hidden link to my site

[angiolo]

I monitor our websites using Google Alert too, just to get some information about new sites linking to our sites in a natural way.

Today I discovered that one of our competitors, in its home page, has an hidden link to one of our sites! That page has a Page rank of 4 and the site is not banned.

I am wondering why he is acting in these way: is there any danger?
Could we be penalized because a site links to us using an hidden link?

That site has other hidden text at the bottom of the home page.
That index text is our menù but without links.

Why having hidden text hidden in the homepage?

[new_seo]

It's really interesting. :)
Can't say why they have done such thing,but I don't think that it is anything danger for you.
The link is one way and I feel in maximum cases a webmaster is not responsible for a one way link to his/her site.

[vincevincevince]

It should be harmless, if it's one link. OTOH, I'd try to get them to remove it.

[martinibuster]

They are linking to you for SEO reasons, the old link-out-to-relevant-sites routine. It's hidden because they don't actually want anyone to follow the link.

People are generally penalized for hosting hidden links, not receiving them. I don't think the search engines are able to spot those algorithmically, either.

[trakkerguy]

Many people feel that linking out to a relevant quality site will help your ranking. He's probably linking to you with keywords he wants to rank for, but doesn't want you to get the traffic, so is hidden.

oops, looks like martinibuster beat me to it...

[angiolo]

Thank you to everybody!
So just get a themed link with some page rank from a page having only one outbond link ( my link)...

[CainIV]

Martini is correct. It's likely they are trying to get a benefit from the outlink to you, which means they think you are doing a good job in your efforts. Its unlikely that link could hurt you, and will likely help you in most cases.

[ecmedia]

If anyone will be hurt it is him - hidden link is no no.

[vincevincevince]

Have a good look at his site for javascript which seems to detect visited links. I saw a script yesterday which would use hidden links to detect if you'd visited the linked site. i.e. it could be competitive research.