Definitely no. For those who don't click links, here's why not:
A standard hdd is divided into sectors. When something gets saved, either permanently or temporarily, stuff gets saved in pieces. One fragment here, another there and so on. During time temporary files get removed, which will create new empty holes for fragments of future savings. It will take quite an effort for the reading head to jump from one fragment to another if they are all over the place. Defragmenting will line the fragments in a sequential order, after which the reading arm movements are far less. For the less tech minded: Think about files and programs as a jigsaw puzzle. Put all pieces together and you'll see a whole picture. Now, kids may want to do several of them in a row, after which they get tired and start messing around, kicking the pieces all around. All of the pieces are still in the playroom, but compiling a single picture would take far more time. Defragmenting is the mom who sorts all the pieces in respective boxes and puts them on the shelf.
SSD's are different. They don't have any mechanically moving parts, whose traveling time can be measured. Thus it doesn't matter whether the fragments were in a single memory block or not. There's no speeding effect in defragmenting an SSD.
An even more important thing is that SSD's only can do a certain amount of rewriting. Although the number is huge and still increasing, there is a limit. Defragmenting does a lot of rewriting all over the disk. Thus defragmenting an SSD will make it wear out faster for nothing.
