You can probably try to smoke anything if you wanted to. The issue of smoking marijuana seeds is interesting though given the answer I have given about legality. Crushing the seeds and smoking them will most likely be less effective than the leaves and plants. This is because the seeds contain little or no THC. There is some suggestion that the protein in the weed seeds will give you a headache when smoked. 

That’s an interesting question. Laws vary in different countries vary but the sale of weed seeds in Ireland and the UK for example is legal but growing the seeds is illegal. It is illegal to grow the seeds for recreational or indeed medical use in most countries. Essentially the seeds by themselves are not harmful and indeed many people feel they have health benefits. You certainly cannot get high from eating the seeds.

I touched on this a little in my answer about ruderalis. Essentially autoflowering cannabis seeds such as Lowryder seeds will go into budding based on age and not on changes in the length of daylight. Therefore they flower with much less effort than the other stains of cannabis. It means that autoflowering cannabis seeds require a little less maintenance, and offer a little more peace of mind to people in countries where it's legal to grow. There are many areas of the world where auto-flowering plants grow wild where hemp cultivation was common such as the Midwest of the USA, Canada, Russia and other Eastern European countries.

Sativa and indica are the two main species of cannabis with sativa being the stronger of the two. Indica is commonly used to make hash and stronger grasses such as skunk, and sativa was traditionally used to make rope and fibers as well as being used recreationally and for medicinal use. One of the differences between the two is the size the plants can grow to. Indica plants usually grow to about 6 foot high, whereas the sativa plants can grow as tall as 25 feet. However sativa plants are usually between 8 and 12 feet tall. In places where weed seeds are grown, they normally find that the sativa leaves are smaller and thinner than indica leaves.  

I mentioned in an earlier answer to a question that ruderalis is a putative species of cannabis. In areas where it is grown, typically central Asia, it tends to flower earlier than indica and sativa and can survive in much harsher climates too. It is also different in that it these are auto-flowering seeds. That is to say they bud after germination based on their age not the amount of light they are exposed to. Whilst they contain little THC, ruderalis plants have big potential for use in breeding, both in hemp and marijuana applications.