Has this left you asking "What's the difference"?
Let's take a look.
Wattage is used to measure energy consumption. Therefore, a 100 watt light bulb used more energy than a 60 watt light bulb. LED technology allows production of light more efficiently using less energy. With that comes the shift to using lumens as the new standard.
Lumen is the unit of measure for the total quantity of light emitted. Using lumens is closer measuring the actual brightness of a light, rather than how much energy it consumes. The lumen count also affects the color.
To save energy, find bulbs with the lumens you need, and then choose the one with the lowest wattage. You can also look for an ENERGY STAR certified bulb that is labeled as equivalent to the standard bulb you are replacing.
Wondering how much light you need? Here's a simple conversion chart provided by ENERGY STAR.
Watts vs. Lumens