I use bookmarks for several different reasons. First, I have bookmarks by location. So I have bookmarks such as "Recipe Box" which is for the hand-written, personal recipes I've added that reside in my recipe box. I also have a bookmark for "Clippings" which indicates that it's in one of my (many!) recipe binders that contain magazine tear-outs & online recipes I've printed out. I then have bookmarks in parentheses that indicate the various divisions I have in my binders, for example (Soups), (Cakes), etc. -- I have 15 categories like this. So let's say I index an online recipe for Chocolate caramel cake and then decide to print it out and put in my binder, I would bookmark it with Clippings & (Cakes).
I also use bookmarks to flag Favorite recipes that I've made and would DEFINITELY make again. I don't bookmark every single recipe that I've simply liked, or that list would get out of control. I have a generic "Favorites" bookmark in case I ever want to search through all of them at once, but I've also just started breaking down my favorites into broad categories, so I now have a couple of bookmarks such as "Favorites - Dinners/Mains," "Favorites - Sweets," "Favorites - Breads & Breakfast," "Favorites - Appetizers," as well. So if I made a stellar stir-fry recipe, I would bookmark it with Favorites & Favorites - Dinner/Mains.
I then have a general "To Try" bookmark which is where I only put the absolute stand-out recipes I find while browsing my collection -- the ones I want to make even if it means a separate trip to the store or tracking down odd ingredients. I am extremely picky with this list to make sure it doesn't get out of hand. I also edit it every once in a while and take recipes off that have lost their luster for me.
I am much more likely to choose recipes based on what I have available to me, than to just create an endless "To Try" list of every recipe that looks good, but after reading the other comments on Susie's blog post about Recipe-Wish lists, I have started making more specific "To Try" bookmarks that are tailored to specific ingredients. So, let's say I'm cleaning out my pantry and find a package of freeze-dried strawberries or a bag of spelt flour that I forgot about and I want to figure out what to do with them. As I'm searching through EYB, I'd create a more specific bookmark, "To Try - Freeze Dried Strawberries" or "To Try - Spelt flour" so I can easily find the recipes I liked when trying to figure out how to use those ingredients. Once I've tried them or finished up the ingredient, I'd delete the bookmark altogether since these ones are just temporary so I don't lose track of things.
I've also started doing the same thing for certain occasions. If I find a recipe and say to myself "That would be perfect for next Thanksgiving" or "That would great to make as a great gift," I've been making bookmarks "To Try - Thanksgiving," "To Try - Gifts," etc. so when that occasion is upon me, I can find those "perfect" recipes that I otherwise might have forgotten about.
For me, the key to all this actually working is being very picky so the lists don't get unruly and editing periodically so that they remain useful to me rather than just one big mess!