An IP address is nothing more than an identifying number assigned to you automatically (usually, with exception to static IP addresses). It identifies what machine on the network is requesting which packets. Unless you are using advanced settings and have manually assigned your own static IP your IP address changes quite frequently, and without warning or you noticing it. I could go much deeper into IP addressing, but all you need to concern yourself with is that they are used to direct packets to the target machine. What does this mean? When you type in a URL and try to access a website that request is sent as a packet to the website you wish to access, the website then returns the data requested as multiple packets being sent back to you. The IP address lets the website know where exactly on your network the packets are being sent. This avoids something such as the website trying to send you router the information, or possibly you r networked printer.
What does this mean as far as hackers go? It can mean a great deal or relatively nothing. See hackers are classified in 3 groups. Whitehat, Greyhat, and Blackhat. Whitehat hackers do not do anything that is not 100% legal and would never try to hack your network without signed permission and a very detailed scope of the attack. A greyhat hacker will do it, but usually for good reasons (Anonymous can be considered Greyhat). Then your blackhat hackers, these guys are the ones trying to steal your information. So why do these guys want your IP? Fact is only one of these 3 groups even care, the Blackhats. The thing about the blackhat hackers is this: YOU RE SMALL POTATOES TO THEM! They target mass groups of people rather than individuals trafficking a website. They want as much information on as many people as possible as quickly as possible, and there are WAY better ways to do this such as using social engineering tactics to have you infect and attack your own machine. See in order for YOUR computer to get hacked I have to scan your network by the given IP, then I have find out what security protocols are in place, and then I have to find and utilize an exploit, this becomes VERY time consuming. This is impractical for the blackhat hacker since they want a mass amount of information. It would be easier to setup a website hosting funny Meme s, or outlandish news articles to draw your attention, reroute you through several websites by using a shortened URL and allow you to infect your machine with malicious code that would send what data I want back to my personal server autonomously without me ever having to actually execute an attack on individual machines. I post this "Click bait" on Facebook and before you know it I have keyloggers and data loggers running on thousands of machines without once using an exploit.
So what does this mean for you? Well most hackers wont post a website about hacking in order to execute a social engineering attack as mentioned above. In fact most hackers wont hack anything they do not own or that they have expressed permission to hack. You visited an informative site and got paranoid due to the subject material. No one who is malicious is going to execute an attack that could take the majority of a day or even longer just to gain information on a random unknown target, after all with all the kids running around the web on their own devices why would I risk anything trying to get bank information that may not even exist?