I think this prevents a problem about copyright 
(even though I'm not sure ;-).
[download]

I think you're 100% wrong about that. It's hardly likely to be an issue in this case, but just because you link back to the site doesn't mean you're OK, definitely not.

I don't want to be boring about it, it's just that I've recently been on a course about these issues which opened my eyes to stuff and everywhere I go now, I see Lawsuits Waiting To Happen... or at least Frosty Cease And Desist Letters Waiting To Be Sent.
--

“Every bit of code is either naturally related to the problem at hand, or else it's an accidental side effect of the fact that you happened to solve the problem using a digital computer.”
M-J D

A little learning is a dangerous thing;
drink deep or taste not the Pierian spring.

In many areas of the law there are judgement calls that need to be made. This is particularly true in intellectual property where there are concepts like "fair use" running around that get settled not according to legislation, but according to precedent. As a result what seems obvious to someone who knows a little may well be utterly not obvious - wrong even - to someone with a deep knowledge of the subject. And getting legal stuff wrong can have very bad consequences. Furthermore you can be sued for misleading someone about what the law is, particularly if your advice gets them into trouble.

This is why you will find that amateur lawyers who know some of the basic stuff (ie enough to be dangerous - like me) often say IANAL (I Am Not A Lawyer). Professionals either will not give advice, or else they will tell you some generalities and then will say, "This is not legal advice." Going and giving people legal advice with the best intentions in the world can get you sued. Lawyers like being paid to put their neck on the line like that. (Or so a couple of lawyers have explained to me...)

In that spirit, IANAL and this is not legal advice. But you can have some confidence that search engines like Google have lawyers, have been through lawsuits already, and are likely to be staying within what they understand to be fair use. So if you stick within the bounds of what they are doing, you are probably going to be OK.

Linking back to the site doesn't automaticly make it not a copyright violation. However, an argument can be made that by linking, you are also attributing, which is at least a start toward fair use. Also, I don't think you can claim copyright protection on somthing so short as a headline... OTOH, if you give the whole first paragraph, that's certianly getting closer to copyright violation.

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Warning: Unless otherwise stated, code is untested. Do not use without understanding. Code is posted in the hopes it is useful, but without warranty. All copyrights are relinquished into the public domain unless otherwise stated. I am not an angel. I am capable of error, and err on a fairly regular basis. If I made a mistake, please let me know (such as by replying to this node).

Well, then I think contacting the webmasters of related sites and telling them the exact data fetching mechanism and asking for their permission can resolve the matter. I don't want to use Perl for any illegal activity no matter how innocent it might seem ;-)