I too am new to plurk but still have learnt a lot within these couple of days. And people there are awesome and friendly, helping in nature. Me being a noob there used to navigate here and there in the site to explore the features in it, but the helpful members are good and they helped me a lot in a few normal plurking tricks. Here i am on plurk. Also check the tips on how to increase karma in plurk.
Listing out a few plurk tricks for you to use while plurking or responsing to a plurk -

Linking to other plurk users - The same like you do in twitter, just add a @ in front of the username whom you want to link to. If you want to link to my profile in your plurk, then just do it as @sizzler_chetan

Making text in your plurk bolded - A single word or few words together can be bolded by just adding double asterisk ** in front and back of the text. For example - **test** will make the word test bolded.

Making text in your plurk italic - Similar to the bold option, but have to add just one asterisk in front and end of the text. - *test*

How to add image to a plurk - Don’t use any codes, just include the direct URL of the image in the plurk. And it comes as a small icon in the plurk message, which opens there itself if you click on it.

Video embedding in the plurk - You don’t need to place the whole embed code which you use for websites, but you can just place the video URL in the plurk, and the video starts along.

Update - More tricks added.

Add a link in the plurk with anchor text - This one is done by many people to make their plurk look smaller and better. Here is the trick -
Link you want to add (Anchor text)
So you first place the link in the message and give a space and then between the brackets, your anchor text. It will get the anchor text hyperlinked in your plurk.

Move along timeline - You can just scroll with your mouse wheel, or right or left arrow keys to move along the timeline and read other’s plurks.

As i said members there are really helpful, one of them shares more -
JimHutchinson -

• Here is a tip: In an active conversation, leave that box open to see replies in real time when they come in.
• Also, to find more friends, monitor active conversations of your interest and request friends from those who participate.
• You could add a section on using the search. It is often overlooked. You can search for people or Plurks by keyword
• The faster you spin the mouse wheel, the quicker time flies by.

I will add more tricks to this post later when people still share more. For those who are still wondering what plurk is, join in and explore what it is.